Rectal cancer outcomes vary significantly according to the stage of disease and prognostic factors, including the distance of the tumor from the circumferential resection margin. Accurate staging allows stratification of patients into low-, moderate-, and high-risk disease, which can be used to inform multidisciplinary team decisions regarding the role of neoadjuvant therapy. This article reviews the management of locally advanced rectal cancer, with particular focus on the importance of appropriate patient selection.
Explain the use of MRI to stratify patients to undergo different neoadjuvant treatment strategies for locally advanced rectal cancer.Identify the benefits and risks of currently available neoadjuvant treatment strategies and appraise emerging treatment strategy.Identify tissue and imaging biomarkers that could predict tumor sensitivity to chemoradiation.
Rectal cancer remains a significant problem worldwide. Outcomes vary significantly according to the stage of disease and prognostic factors, including the distance of the tumor from the circumferential resection margin. Accurate staging, including high-resolution magnetic resonance imaging, allows stratification of patients into low-, moderate-, and high-risk disease; this information can be used to inform multidisciplinary team decisions regarding the role of neoadjuvant therapy. Both neoadjuvant short-course radiotherapy and long-course chemoradiation reduce the risk of local recurrence compared with surgery alone, but they have little impact on survival. Although there remains a need to reduce overtreatment of those patients at moderate risk, evaluation of intensified regimens for those with high-risk disease is still required to reduce distant failure rates and improve survival in these patients with an otherwise poor prognosis.
Rectal cancer; Chemoradiation; Magnetic resonance imaging; Neoadjuvant treatment
Oesophageal junctional adenocarcinoma is a challenging and increasingly common disease. Optimisation of pre-operative staging and consolidation of surgery in large volume centres have improved outcomes, however the preferred adjunctive treatment approach remains a matter of debate. This review examines the benefits of neoadjuvant, peri-operative, and post-operative chemotherapy and chemoradiotherapy in this setting in an attempt to reach an evidence based conclusion. Recent findings relating to the molecular characterisation of oesophagogastric cancer and their impact on therapeutics are explored, in addition to the potential benefits of fluoro-deoxyglucose positron emission tomography (FDG-PET) directed therapy. Finally, efforts to decrease the incidence of junctional adenocarcinoma using early intervention in Barrett’s oesophagus are discussed, including the roles of screening, endoscopic mucosal resection, ablative therapies and chemoprevention.
Oesophageal adenocarcinoma; Junctional adenocarcinoma; Gastric adenocarcinoma; Peri-operative chemotherapy; Pre-operative chemoradiotherapy; Molecular profiling; Fluoro-deoxyglucose-positron emission tomography; Barrett’s oesophagus; Chemoprevention
The MET/hepatocyte growth-factor (HGF) signaling pathway plays a key role in the processes of embryogenesis, wound healing, and organ regeneration. Aberrant activation of MET/HGF occurs through multiple mechanisms including gene amplification, mutation, protein overexpression, and abnormal gene splicing interrupting autocrine and paracrine regulatory feedback mechanisms. In many cancers including non-small-cell lung cancer, colorectal, gastric, renal, and hepatocellular cancer, dysregulation of MET may lead to a more aggressive cancer phenotype and may be a negative prognostic indicator. Successful therapeutic targeting of the MET/HGF pathway has been achieved using monoclonal antibodies against the MET receptor and its ligand HGF in addition to MET-specific and multitargeted small-molecule tyrosine-kinase inhibitors with several drugs in late-phase clinical trials including onartuzumab, rilotumumab, tivantinib, and cabozantinib. MET frequently interacts with other key oncogenic tyrosine kinases including epidermal growth-factor receptor (EGFR) and HER-3 and these interactions may be responsible for resistance to anti-EGFR therapies. Similarly, resistance to MET inhibition may be mediated through EGFR activation, or alternatively by increasing levels of MET amplification or acquisition of novel “gatekeeper” mutations. In order to optimize development of effective inhibitors of the MET/HGF pathway clinical trials must be enriched for patients with demonstrable MET-pathway dysregulation for which robustly standardized and validated assays are required.
MET; HGF; colorectal cancer; gastric cancer; NSCLC; renal cancer; hepatocellular cancer; onartuzumab; rilotumumab; cabozantinib
In general practice internationally, many care teams handle large numbers of laboratory test results relating to patients in their care. Related research about safety issues is limited with most of the focus on this workload from secondary care and in North American settings. Little has been published in relation to primary health care in the UK and wider Europe. This study aimed to explore experiences and perceptions of patients with regards to the handling of test results by general practices.
A qualitative research approach was used with patients. The setting was west of Scotland general practices from one National Health Service territorial board area. Patients were purposively sampled from practice held lists of patients who received a number of laboratory tests because of chronic medical problems or surveillance of high risk medicines. Focus groups were held and were audio-recorded. Tapes were transcribed and subjected to qualitative analysis. Transcripts were coded and codes merged into themes by two of the researchers.
19 participants from four medical practices took part in four focus groups. The main themes identified were: 1. Patients lacked awareness of the results handling process in their practice. 2. Patients usually did not contact their practice for test results, unless they considered themselves to be ill. 3. Patients were concerned about the appropriateness of administrators being involved in results handling. 4. Patients were concerned about breaches of confidentiality when administrators were involved in results handling. 5. Patients valued the use of dedicated results handling staff. 6. Patients welcomed the use of technology to alert them to results being available, and valued the ability to choose how this happened.
The study confirms the quality and safety of care problems associated with results handling systems and adds to our knowledge of the issues that impact in these areas. Practices need to be aware that patients may not contact them about results, and they need to publicise their results handling processes to patients and take steps to reassure patients about confidentiality with regards to administrators.
Aging-related weakness is due in part to degeneration within the central nervous system. However, it is unknown how changes to the representation of corticospinal output in the primary motor cortex (M1) relate to such weakness. Transcranial magnetic stimulation (TMS) is a noninvasive method of cortical stimulation that can map representation of corticospinal output devoted to a muscle. Using TMS, we examined age-related alterations in maps devoted to biceps brachii muscle to determine whether they predicted its age-induced weakness. Forty-seven right-handed subjects participated: 20 young (22.6±0.90 years) and 27 old (74.96±1.35 years). We measured strength as force of elbow flexion and electromyographic activation of biceps brachii during maximum voluntary contraction. Mapping variables included: 1) center of gravity or weighted mean location of corticospinal output, 2) size of map, 3) volume or excitation of corticospinal output, and 4) response density or corticospinal excitation per unit area. Center of gravity was more anterior in old than in young (p<0.001), though there was no significant difference in strength between the age groups. Map size, volume, and response density showed no significant difference between groups. Regardless of age, center of gravity significantly predicted strength (β = −0.34, p = 0.005), while volume adjacent to the core of map predicted voluntary activation of biceps (β = 0.32, p = 0.008). Overall, the anterior shift of the map in older adults may reflect an adaptive change that allowed for the maintenance of strength. Laterally located center of gravity and higher excitation in the region adjacent to the core in weaker individuals could reflect compensatory recruitment of synergistic muscles. Thus, our study substantiates the role of M1 in adapting to aging-related weakness and subtending strength and muscle activation across age groups. Mapping from M1 may offer foundation for an examination of mechanisms that preserve strength in elderly.
Persistent signaling by the oncogenic epidermal growth factor receptor (EGFR) is a major source of cancer resistance to EGFR targeting. We established that inactivation of two sterol biosynthesis pathway genes, SC4MOL (sterol C4-methyl oxidase-like) and its partner NSDHL (NADP-dependent steroid dehydrogenase-like), sensitized tumor cells to EGFR inhibitors. Bioinformatics modeling of interactions for the sterol pathway genes in eukaryotes allowed us to hypothesize, and then extensively validate an unexpected role for SC4MOL and NSDHL in controlling the signaling, vesicular trafficking and degradation of EGFR and its dimerization partners, ERBB2 and ERBB3. Metabolic block upstream of SC4MOL with ketoconazole or CYP51A1 siRNA rescued cancer cell viability and EGFR degradation. Inactivation of SC4MOL markedly sensitized A431 xenografts to cetuximab, a therapeutic anti-EGFR antibody. Analysis of Nsdhl-deficient Bpa1H/+ mice confirmed dramatic and selective loss of internalized PDGFR in fibroblasts, and reduced activation of EGFR and its effectors in regions of skin lacking NSDHL.
This review examines emerging molecular targets and novel therapeutic agents in diffuse large B-cell lymphoma (DLBCL). In particular, it discusses whether stratifying therapy for DLBCL using molecular features is merited by current preclinical and clinical evidence.
After completing this course, the reader will be able to:
Describe the oncogenic drivers in DLBCL, especially those that have recently been identified, and how they relate to the oncogenic DLBCL subtypes.Describe the prognostic and potentially predictive implications of DLBCL COO subtype for chemotherapy and rituximab.Outline the evidence for novel targeted therapies and therapeutic strategies in DLBCL, how they may be stratified by DLBCL subtype or to specific tumor molecular features, and how these strategies can be incorporated into current treatment paradigms and prospective clinical trial design.
This article is available for continuing medical education credit at CME.TheOncologist.com
The division of the heterogeneous entity of diffuse large B-cell lymphoma (DLBCL) into the ontogenic phenotypes of germinal center B-cell-like (GCB) and activated B-cell-like (ABC) is optimally determined by gene expression profiling (GEP), although simpler immunohistochemistry (IHC) algorithms are alternatively being used. The cell-of-origin (COO) classification assists in prognostication and may be predictive of response to therapy. Mounting data suggests that IHC methods of classifying COO may be inaccurate. GEP categorization of COO is superior in defining prognostically and biologically distinct DLBCL subtypes, but current barriers to its widescale use include inaccessibility, cost, and lack of methodological standardization and prospective validation. The poorer prognosis of ABC-DLBCL is frequently associated with constitutive activity in the NF-κB pathway and aberrations in upstream or downstream regulators of this pathway. The molecular mechanisms underlying lymphomagenesis in GCB-DLBCL are arguably less well defined, but C-REL amplification and mutations in BCL-2 and EZH2 are common. New technologies, such as next-generation sequencing, are rapidly revealing novel pathogenic genetic aberrations, and DLBCL treatment strategies are increasingly being designed focusing on distinctive pathogenic drivers within ontogenic phenotypes. This review examines emerging molecular targets and novel therapeutic agents in DLBCL, and discusses whether stratifying therapy for DLBCL using molecular features is merited by current preclinical and clinical evidence.
Lymphoma, large B-cell, diffuse; Gene expression profiling; Molecular targeted therapy; Drug therapy; Immunohistochemistry; Phenotype
More than 60% of stroke survivors experience residual deficits of the paretic upper limb/hand. Standard rehabilitation generates modest gains. Stimulation delivered to the surviving Primary Motor Cortex in the stroke-affected hemisphere has been considered a promising adjunct. However, recent trials challenge its advantage. We discuss our pilot clinical trial that aims to address factors implicated in divergent success of the approach. We assess safety, feasibility and efficacy of targeting an alternate locus during rehabilitation- the premotor cortex. In anticipating variance across patients, we measure neural markers differentiating response from non-response.
In a randomized, sham-controlled, double-blinded pilot clinical study, patients with chronic stroke (n = 20) are assigned to receive transcranial direct current stimulation delivered to the premotor cortex or sham during rehabilitation of the paretic arm/hand. Patients receive the designated intervention for 30 min, twice a day for 3 days a week for 5 weeks. We assess hand function and patients’ reports of use of paretic hand. A general linear mixed methods model will analyze changes from pre- to post-intervention. Responders and non-responders will be compared upon baseline level of function, and neural substrates, including function and integrity of output tracts, bi-hemispheric balance, and lesion profile. Incidence of adverse events will be compared using Fisher’s Exact test, while rigor of blinding will be assessed with Chi-square analysis to ascertain feasibility.
Variable success of cortical stimulation in rehabilitation can be related to gaps in theoretical basis and clinical investigation. Given that most patients with severe deficits have damage to the primary motor cortex or its output pathways, it would be futile to target stimulation to this site. We suggest targeting premotor cortex because it contributes substantially to descending output, a role that is amplified with greater damage to the motor cortex. With regards to clinical investigation, paired cortical stimulation in rehabilitation has been compared to rehabilitation alone in unblinded trials or to unconvincing sham conditions. Transcranial direct current stimulation, a noninvasive technique of brain stimulation, which offers a more effective placebo and has a favorable safety-feasibility profile, may improve scientific rigor. Neural markers of response would help inform patient selection for future clinical trials so we can address limitations of recent negative studies.
Stroke; Rehabilitation; Brain stimulation; Motor cortex (M1); Premotor cortex (PMC); Diffusion tensor imaging (DTI); Functional magnetic resonance imaging (fMRI); Resting state functional magnetic resonance imaging (rs-fMRI); Transcranial magnetic stimulation (TMS); Transcranial direct current stimulation (tDCS)
Advances in the treatment of metastatic colorectal cancer have led to an improvement in survival from 12 months with fluorouracil monotherapy to approximately 2 years. This is partly as a result of the addition of irinotecan and oxaliplatin, but is also due to the use of monoclonal antibodies against the epidermal growth factor receptor (EGFR) and antiangiogenic drugs such as bevacizumab. However, there are significant molecular differences between tumours which can affect both prognosis and response to treatment. Personalized medicine aims to tailor treatment according to the characteristics of the individual patient and is now a clinical reality as testing for KRAS mutations to guide treatment with the anti-EGFR monoclonal antibodies cetuximab and panitumumab is now part of routine clinical practice. However, not all patients who are KRAS wild type respond to anti-EGFR therapy and a validated biomarker for antiangiogenic therapy is still lacking. Therefore, other biomarkers are needed to assist with predicting response to both existing drugs as well as to drugs currently under investigation. This review summarizes the molecular biology of colorectal cancer, focusing on the genetic features that are currently most clinically relevant. Current and emerging biomarkers are reviewed along with their roles in selecting patients for targeted treatment with currently licensed therapies and drugs being evaluated in clinical trials. The value of predictive biomarkers of chemosensitivity and potential future treatment strategies are also discussed.
biomarker; colorectal cancer; personalized medicine; targeted therapy
EGFR overexpression occurs in 27–55% of oesophagogastric adenocarcinomas, and correlates with poor prognosis. We aimed to assess addition of the anti-EGFR antibody panitumumab to epirubicin, oxaliplatin, and capecitabine (EOC) in patients with advanced oesophagogastric adenocarcinoma.
In this randomised, open-label phase 3 trial (REAL3), we enrolled patients with untreated, metastatic, or locally advanced oesophagogastric adenocarcinoma at 63 centres (tertiary referral centres, teaching hospitals, and district general hospitals) in the UK. Eligible patients were randomly allocated (1:1) to receive up to eight 21-day cycles of open-label EOC (epirubicin 50 mg/m2 and oxaliplatin 130 mg/m2 on day 1 and capecitabine 1250 mg/m2 per day on days 1–21) or modified-dose EOC plus panitumumab (mEOC+P; epirubicin 50 mg/m2 and oxaliplatin 100 mg/m2 on day 1, capecitabine 1000 mg/m2 per day on days 1–21, and panitumumab 9 mg/kg on day 1). Randomisation was blocked and stratified for centre region, extent of disease, and performance status. The primary endpoint was overall survival in the intention-to-treat population. We assessed safety in all patients who received at least one dose of study drug. After a preplanned independent data monitoring committee review in October, 2011, trial recruitment was halted and panitumumab withdrawn. Data for patients on treatment were censored at this timepoint. This study is registered with ClinicalTrials.gov, number NCT00824785.
Between June 2, 2008, and Oct 17, 2011, we enrolled 553 eligible patients. Median overall survival in 275 patients allocated EOC was 11·3 months (95% CI 9·6–13·0) compared with 8·8 months (7·7–9·8) in 278 patients allocated mEOC+P (hazard ratio [HR] 1·37, 95% CI 1·07–1·76; p=0·013). mEOC+P was associated with increased incidence of grade 3–4 diarrhoea (48 [17%] of 276 patients allocated mEOC+P vs 29 [11%] of 266 patients allocated EOC), rash (29 [11%] vs two [1%]), mucositis (14 [5%] vs none), and hypomagnesaemia (13 [5%] vs none) but reduced incidence of haematological toxicity (grade ≥3 neutropenia 35 [13%] vs 74 [28%]).
Addition of panitumumab to EOC chemotherapy does not increase overall survival and cannot be recommended for use in an unselected population with advanced oesophagogastric adenocarcinoma.
Amgen, UK National Institute for Health Research Biomedical Research Centre.
The phosphoinositide 3-kinase-AKT-mammalian target of rapamycin (PI3K-AKT-mTOR) pathway is a frequently hyperactivated pathway in cancer and is important for tumor cell growth and survival. The development of targeted therapies against mTOR, a vital substrate along this pathway, led to the approval of allosteric inhibitors, including everolimus and temsirolimus, for the treatment of breast, renal, and pancreatic cancers. However, the suboptimal duration of response in unselected patients remains an unresolved issue. Numerous novel therapies against critical nodes of this pathway are therefore being actively investigated in the clinic in multiple tumour types. In this review, we focus on the progress of these agents in clinical development along with their biological rationale, the need of predictive biomarkers and various combination strategies, which will be useful in counteracting the mechanisms of resistance to this class of drugs.
PI3K-AKT-mTOR; PTEN; RTK; signaling pathways; molecular therapeutics
Source data verification (SDV) is a resource intensive method of quality assurance frequently used in clinical trials. There is no empirical evidence to suggest that SDV would impact on comparative treatment effect results from a clinical trial.
Data discrepancies and comparative treatment effects obtained following 100% SDV were compared to those based on data without SDV. Overall survival (OS) and Progression-free survival (PFS) were compared using Kaplan-Meier curves, log-rank tests and Cox models. Tumour response classifications and comparative treatment Odds Ratios (ORs) for the outcome objective response rate, and number of Serious Adverse Events (SAEs) were compared. OS estimates based on SDV data were compared against estimates obtained from centrally monitored data.
Data discrepancies were identified between different monitoring procedures for the majority of variables examined, with some variation in discrepancy rates. There were no systematic patterns to discrepancies and their impact was negligible on OS, the primary outcome of the trial (HR (95% CI): 1.18(0.99 to 1.41), p = 0.064 with 100% SDV; 1.18(0.99 to 1.42), p = 0.068 without SDV; 1.18(0.99 to 1.40), p = 0.073 with central monitoring). Results were similar for PFS. More extreme discrepancies were found for the subjective outcome overall objective response (OR (95% CI): 1.67(1.04 to 2.68), p = 0.03 with 100% SDV; 2.45(1.49 to 4.04), p = 0.0003 without any SDV) which was mostly due to differing CT scans.
Quality assurance methods used in clinical trials should be informed by empirical evidence. In this empirical comparison, SDV was expensive and identified random errors that made little impact on results and clinical conclusions of the trial. Central monitoring using an external data source was a more efficient approach for the primary outcome of OS. For the subjective outcome objective response, an independent blinded review committee and tracking system to monitor missing scan data could be more efficient than SDV.
The majority of gastric cancer patients present with advanced, incurable disease and only a minority have localised disease that is suitable for radical treatment. A benefit has generally been demonstrated from adding chemotherapy to surgery for early disease though there are marked differences in how this is done globally. Whilst a perioperative approach, with chemotherapy given before and after gastric surgery is commonly used in the Europe and Australia most patients with operable gastric cancer in North America are treated with surgery and postoperative chemoradiation. In contrast, in East Asia, adjuvant fluoropyrimidine chemotherapy alone is used following D2 gastric resection surgery. However, despite the multimodality treatments, outcomes remain suboptimal as the majority of those treated for localised disease eventually relapse with incurable loco-regional or distant metastases. At the current time, an unmet need exists to further understand the biology of this aggressive disease and develop more efficacious therapies that can improve outcomes from this aggressive disease.
Operable gastric cancer; Chemotherapy
The human epidermal receptor-2 (HER-2) is amplified in up to 25% of patients with gastroesophageal adenocarcinomas. Although the presence of this amplification does not appear to confer a poor prognosis, it provides a valuable novel therapeutic target for this group of patients. Trastuzumab is a fully humanized monoclonal antibody directed at HER-2 which binds the external domain of the receptor and exerts its action via a combination of antibody-dependent cytotoxicity, reduced shedding of the extracellular domain, inhibition of dimerization and possibly receptor downregulation. The ToGA trial was an international multicentre randomized phase III study which evaluated the addition of trastuzumab to a cisplatin plus fluoropyrimidine chemotherapy doublet in 594 patients with HER-2-positive advanced gastric or oesophagogastric junction adenocarcinoma. The combination of the antibody with chemotherapy significantly improved response rate, median progression-free survival and median overall survival without additional toxicity or adversely affecting quality of life. Accordingly, trastuzumab plus chemotherapy is now a standard first-line treatment option for patients with advanced HER-2-positive gastroesophageal cancer. Unfortunately, many patients with HER-2-positive cancer exhibit primary resistance to trastuzumab and the remainder will acquire resistance to the antibody; therefore, urgent investigation into novel agents which may circumvent resistance mechanisms is warranted. Small molecule inhibitors of HER-2, which commonly also target other members of the HER family of receptors, such as EGFR and HER-3, are currently undergoing evaluation in gastroesophageal cancer as first-line alternatives to trastuzumab and second-line salvage treatments for trastuzumab-resistant disease. Extrapolating the successful use of trastuzumab in the advanced disease setting, clinical trials are underway to assess the role of this antibody in the perioperative and adjuvant settings, where it is hoped that it will have a meaningful impact upon the currently poor survival rates.
adenocarcinoma; gastric cancer; HER-2; monoclonal antibody; oesophagogastric junction (OGJ); trastuzumab; tyrosine kinase inhibitor
Surgery is often advocated in patients with resectable pulmonary metastases from colorectal cancer (CRC). Our study aims to evaluate peri-operative chemotherapy in patients with metastastic CRC undergoing pulmonary metastasectomy.
Patients treated for CRC who underwent pulmonary metastasectomy by a single surgeon were identified. Outcome measures included survival, peri-operative complications, radiological and histological evidence of chemotherapy-induced lung toxicities.
Between 1997 and 2009, 51 eligible patients were identified undergoing a total of 72 pulmonary resections. Thirty-eight patients received peri-operative chemotherapy, of whom 9 received an additional biological agent. Five-year overall survival rate was 72% in the whole cohort - 74% and 68% in those who received peri-operative chemotherapy (CS) and those who underwent surgery alone (S) respectively. Five-year relapse free survival rate was 31% in the whole cohort - 38% and ≤18% in CS and S groups respectively. Only 8% had disease progression during neoadjuvant chemotherapy. There were no post-operative deaths. Surgical complications occurred in only 4% of patients who received pre-operative chemotherapy. There was neither radiological nor histological evidence of lung toxicity in resected surgical specimens.
Peri-operative chemotherapy can be safely delivered to CRC patients undergoing pulmonary metastasectomy. Survival in this selected group of patients was favourable.
Colorectal cancer; lung resection; peri-operative chemotherapy
The human immunodeficiency virus type 1 (HIV-1) promoter or long-terminal repeat (LTR) regulates viral gene expression by interacting with multiple viral and host factors. The viral transactivator protein Tat plays an important role in transcriptional activation of HIV-1 gene expression. Functional domains of Tat and its interaction with transactivation response element RNA and cellular transcription factors have been examined. Genetic variation within tat of different HIV-1 subtypes has been shown to affect the interaction of the viral transactivator with cellular and/or viral proteins, influencing the overall level of transcriptional activation as well as its action as a neurotoxic protein. Consequently, the genetic variability within tat may impact the molecular architecture of functional domains of the Tat protein that may impact HIV pathogenesis and disease. Tat as a therapeutic target for anti-HIV drugs has also been discussed.
Structural and sequence variation have been described in several members of the contactin (CNTN) and contactin associated protein (CNTNAP) gene families in association with neurodevelopmental disorders, including autism. Using array comparative genome hybridization (CGH), we identified a maternally inherited ~535 kb deletion at 3p26.3 encompassing the 5′ end of the contactin 4 gene (CNTN4) in a patient with autism. Based on this finding and previous reports implicating genomic rearrangements of CNTN4 in autism spectrum disorders (ASDs) and 3p− microdeletion syndrome, we undertook sequencing of the coding regions of the gene in a local ASD cohort in comparison with a set of controls. Unique missense variants were identified in 4/75 unrelated individuals with an ASD, as well as in 1/107 controls. All of the amino acid substitutions were nonsynonomous, occurred at evolutionarily conserved positions, and were, thus, felt likely to be deleterious. However, these data did not reach statistical significance, nor did the variants segregate with disease within all of the ASD families. Finally, there was no detectable difference in binding of two of the variants to the interacting protein PTPRG in vitro. Thusadditional, larger studies will be necessary to determine whether CNTN4 functions as an autism susceptibility locus in combination with other genetic and/or environmental factors.
contactin 4; autism; autism spectrum disorder; 3p26 deletion; contactins; susceptibility locus
This review focuses on the rationale for targeting angiogenesis in oncology and the current and possible future applications of antiangiogenic agents in esophagogastric adenocarcinoma.
After completing this course, the reader will be able to:
Describe the receptors and ligands with identified roles in tumor angiogenesis and the mechanism of action of established and investigational antiangiogenic agents.Describe aspects of antiangiogenic agents that are incompletely understood and need further investigation to define their role in esophagogastric cancer.
This article is available for continuing medical education credit at CME.TheOncologist.com
The possibility of targeting tumor angiogenesis was postulated almost 40 years ago. The vascular endothelial growth factor (VEGF) family and its receptors have since been characterized and extensively studied. VEGF overexpression is a common finding in solid tumors, including esophagogastric cancer, and frequently correlates with poor prognosis. Monoclonal antibodies, soluble receptors, and small-molecule tyrosine kinase inhibitors have been developed to inhibit tumor angiogenesis, and antiangiogenic therapy is now a component of standard treatment for advanced renal cell, hepatocellular, colorectal, breast, and non-small cell lung carcinomas. The small-molecule tyrosine kinase inhibitors sunitinib and sorafenib have been evaluated in phase II studies in esophagogastric cancer but appear to have only modest activity. Similarly, despite promising efficacy signals from phase II studies, the addition of the anti-VEGF-A monoclonal antibody bevacizumab to cisplatin plus capecitabine failed to result in a longer overall survival duration than with the chemotherapy doublet plus placebo. The response rate and progression-free survival interval were significantly greater with bevacizumab, confirming some efficacy in advanced gastric cancer, but with inadequate benefit to justify the high cost of treatment. Evaluation of bevacizumab in the neoadjuvant and perioperative settings continues, hypothesizing that a higher response rate will translate into longer survival in patients with operable disease. Despite extensive research, the discovery of a reliable predictive biomarker for antiangiogenic therapy continues to elude the scientific and oncology communities, and mechanisms of primary and acquired resistance are incompletely understood. We are therefore currently unable to personalize antiangiogenic therapy for established indications, or use molecular selection for clinical trials evaluating novel indications.
Angiogenesis; Bevacizumab; Biomarkers; Gastric cancer; Esophageal cancer; VEGF
Mutations in the gene encoding the cholesterol biosynthetic enzyme NSDHL are associated with the X-linked male-lethal bare patches (Bpa) mouse. Mutant male embryos for several Nsdhl alleles die in midgestation with placental insufficiency. We examined here a possible role of the maternal genotype in such placental pathology. Pre-pregnancy plasma cholesterol levels were similar between wild-type (WT) and Bpa1H/+ dams fed a standard, cholesterol-free diet. However, there was a marked decrease in cholesterol levels between embryonic day (E)8.5 and E10.5 for both genotypes. Further, there was a significant lag between E11.5 and E13.5 (P = 0.0011) in the recovery of levels in Bpa1H/+ dams to their pre-pregnancy values. To investigate possible effects of the maternal genotype on fetal placentation, we generated transgenic mice that expressed human NSDHL and rescued the male lethality of the Bpa1H null allele. We then compared placenta area at E10.5 in WT and Bpa1H/+ female embryos where the mutant X chromosome was transmitted from a heterozygous mother or a rescued mutant father. In mutant conceptuses, placental areas were ∼50% less than WT. Surprisingly, expression of Nsdhl in trophoblast lineages of the placenta and yolk sac endoderm, which occurs only from the maternally inherited allele in a female embryo, had the largest effect on placental area (−0.681 mm2; P < 0.0001). The maternal genotype had a smaller effect, independent of the fetal genotype (−0.283 mm2; P = 0.024). These data demonstrate significant effects of the mother and fetal membranes on pregnancy outcome, with possible implications for cholesterol homeostasis during human pregnancy.
NSDHL (NAD(P)H sterol dehydrogenase-like), is a 3β-hydroxysterol dehydrogenase thought to function in the demethylation of sterol precursors in one of the later steps of cholesterol biosynthesis. Mutations in the X-linked NSDHL gene cause CHILD syndrome in humans, and the male-lethal bare patches (Bpa) phenotype in mice. The relative level of NSDHL expression among different mouse tissues at several stages of embryogenesis and postnatal development was analyzed by immunohistochemistry. In wild type (WT) embryos, the highest levels of expression were seen in the liver, dorsal root ganglia, central nervous system, retina, adrenal gland and testis. Heterozygous Bpa1H females are mosaic for NSDHL expression due to normal random X inactivation. NSDHL deficient cells were detected in the developing cerebral cortex and retina of Bpa1H female embryos. In postnatal WT and Bpa1H animals, we compared the expression pattern of NSDHL in skin, an affected tissue; liver, a main site of cholesterol synthesis; and brain, a tissue dependent on endogenous synthesis of cholesterol due to lack of transport across the blood-brain barrier. Clonal populations of mutant cells were visible in the brain, skin and liver of Bpa1H pups. In the liver, the proportion of NSDHL negative cells dropped from ~50% at postnatal day 6 to ~20% at one year of age. In the brain, which showed the highest expression in cerebral cortical and hippocampal neurons, the proportion of NSDHL negative cells also dropped dramatically over the first year of life. Our results suggest that while NSDHL deficient cells in the mosaic Bpa1H female are able to survive and differentiate during embryonic development, they are subject to negative selection over the life of the animal.
Overview of the Disease ProcessIncidencePrognostic or Predictive FactorsCurrent General Therapy StandardsSurgeryAdjuvant ChemoradiationPerioperative ChemotherapyAdjuvant Oral Fluoropyrimidine MonotherapyAccomplishments in 2008TherapyBiomarkers and Basic ScienceWhat Needs to Be DoneApplications of the AccomplishmentsControversies and DisagreementsSpecial PopulationsCurrent and Future DirectionsComments on ResearchObstacles to Progress
Toxicity from chemotherapy is highly variable, unpredictable and results in substantial morbidity and increased healthcare costs. New predictors of toxicity are required to improve the safety and efficacy of chemotherapy. Inflammatory or B symptoms in lymphoma are associated with elevated plasma inflammatory markers and predict worse treatment response and survival. Recent data suggest that systemic inflammation results in reduced hepatic drug metabolism and increased toxicity from chemotherapy. We investigated whether B symptoms were associated with greater toxicity in patients treated for non-Hodgkin lymphoma (NHL).
The British National Lymphoma Investigation compared two chemotherapy regimens in older patients with aggressive NHL. Approximately 50% of patients had B symptoms. Demographic and toxicity data on 664 patients were analysed to identify predictors of toxicity by multivariate analysis, with particular reference to B symptoms.
Using univariate analyses, severe (grades 3–4) leucopenia, anaemia, thrombocytopenia, nausea and vomiting and diarrhoea occurred more frequently in patients with B symptoms. The associations between B symptoms and severe leucopenia (OR 1.7, p = 0.005) and anaemia (OR 2.3, p = 0.025) persisted after adjustment for other prognostic factors in multivariate analyses. The use of granulocyte colony stimulating factor reduced neutropenia in patients with both A and B symptoms.
For the first time and in a large NHL cohort we have shown that inflammatory symptoms are independent predictors for myelosuppression from chemotherapy. These data will enable improved prognostication for toxicity and provide individualisation of therapy in NHL and other tumours. These findings also create the potential for strategies used prior to chemotherapy aimed at reducing systemic inflammation in order to improve drug metabolism and reduce treatment-related toxicity.
Trial registration number
Recent meta-analyses have found a survival advantage with gemcitabine based combinations over single agent gemcitabine in patients with advanced pancreatic cancer. There is paucity of evidence in the form of direct head-to-head randomised controlled trials to determine which combinations are to be preferred.
Using the adjusted indirect comparison method proposed by Bucher et al, we have assessed randomised controlled trials of four gemcitabine based combinations namely gemcitabine plus a platinum compound or 5-fluorouracil or irinotecan or capecitabine.
No particular combination was significantly superior to another, but the indirect evidence suggests some important trends.
The strongest trends on indirect comparison are towards favouring gemcitabine plus capecitabine or gemcitabine plus a platinum compound over gemcitabine plus irinotecan, and to a lesser degree, over gemcitabine plus 5-fluorouracil.
Pancreatic cancer is a largely chemo-resistant disease with a poor prognosis. Despite the adoption of gemcitabine monotherapy as a standard of care, outcomes remain poor. Until recently randomized phase III studies have not demonstrated superiority of various cytotoxic combinations or a number of the newer biologic targeted drugs. The situation has changed with capecitabine and erlotinib, either of which in combination with gemcitabine produces a small increase in survival. Erlotinib is a small molecule tyrosine kinase inhibitor against epidermal growth factor receptor which has an important role in the molecular pathogenesis of pancreatic cancer. In both pre-clinical and early clinical evaluation it has shown anti-tumor activity against pancreatic cancer in combination with gemcitabine. A randomized phase III study in locally advanced and metastatic pancreatic cancer has shown a survival advantage for the combination of gemcitabine plus erlotinib over gemcitabine alone. The rationale for the clinical development of erlotinib in combination with gemcitabine in pancreatic cancer culminating in this randomized trial, together with pharmacologic, toxicity and patient selection considerations form the focus of this review.
erlotinib; tarceva; capecitabine; xeloda; gemcitabine; epidermal growth factor receptor; pancreas; pancreatic